1. Field of the Invention
This invention pertains to a device for collecting body fluid from a subject, and more particularly, to a device which reduces the risk of cross-contamination between the subject and medical personnel.
2. Background of the Prior Art
The recent AIDS epidemic adds a serious and deadly risk factor to taking samples for analysis of a patient's blood. Blood collection devices utilize a needle inserted into a subject's vein so as to draw the blood through the needle into an associated collection reservoir. Accidental needle sticks from previously used needles can occur during the fluid withdrawing process, and subsequent handling and disposal operations.
The most commonly used blood sampling device is sold under the trademark Vacutainer.RTM. by Becton Dickinson Corporation. The conventional device of this type has a tubular syringe-like body with a needle in the end, part of which extends back into the tubular syringe-like shell, and part of which extends externally for puncturing the skin. An evacuated collection tube with a rubber stopper is placed into the open back end of the syringe-like shell with the rubber stopper against the internal end of the needle. After the skin is punctured, the collection tube is pushed to cause the needle to enter the evacuated tube, which helps draw blood into the collecting tube. When a sufficient sample has been obtained, the collecting tube and its stopper are simply withdrawn from the tubular shell and sent to the laboratory. The needle is permanently extended from the end of the syringe-like shell into which the collecting tube is placed. Consequently, great care is required in handling a used device.
Some devices used for sampling body fluids employ a needle assembly which is threadably engaged with a needle-holding syringe-like tube. The needle end for insertion into front needle end for puncturing the vein of the patient and a rear needle end for insertion into an evacuated collection tube. After use, the needle assembly is manually handled. It must be unscrewed for disposal or sterilization. Other devices of this type employ a front mounted needle assembly held by an externally positioned latch mechanism which enables the provider to release the needle assembly frontwardly for disposal. The contaminated needle continues to present a danger to those handling the disposal of waste materials. The needle assembly may be forwardly biased with a spring. An example of this type is found in Wanamaker U.S. Pat. No. 4,841,985.
Still other devices provide for retraction of the needle into a shielded safety syringe. There is a cylindrical outer protective sheath and an inner needle carrier movable axially through the sleeve. The needle carrier has a rearwardly biased needle mounted in an inner slidable sleeve within the outer sheath. A position control body connected to the needle carrier extends through a slot in the outer sleeve and is manually movable to allow the needle to be retracted. However, the needle can be re-extended. The retraction is not permanent. Such a device is illustrated by Haber U.S. Pat. No. 4,813,426. Such devices require complicated parts and are expensive to manufacture and assemble.
It would be desirable to have a retractable fluid collection device having few easily assembled economically mass-produced parts which is automatically and permanently retractable. It would be desirable to have such a device which provides a shifting position in which the needle is enclosed without the need for a separate needle guard and easily extended for use without a need to handle or assemble the needle to another part. It would be desirable to have such a device in which consistent reproducible retraction is assured so that the contaminated needle is fully contained within a protective sheath and one in which the retractive mechanism does not depend upon flexing or breaking of pans.
The invention disclosed herein provides the aforesaid features. Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings in which an embodiment of this invention is set forth by illustration and example.